Automated street sweeping vehicles are essential equipment for commercial and government organizations. The vehicles are used for cleaning debris from roadways, walkways, parking lots, runways, and many other ground surfaces.
For streets and highways, large sweepers are primarily used. The large sweepers are motorized (typically diesel powered) and can be custom-made or built upon a standard commercial truck chassis. The large sweepers typically include large main brushes which direct debris onto a paddled conveyor that moves the debris into a large-capacity debris hopper. The large hoppers allow the sweepers to cover greater distances without the need for emptying the hopper. The large brushes allow the sweeper to pick up larger debris (e.g. rocks, tire treads, wood pieces), thus avoiding the need for multiple passes of the sweeper or manual retrieval of the debris.
Although effective, such street sweepers often miss a certain percentage of the debris, even when the sweeper passes directly over the debris. In some cases, the debris gets caught up in the brush and passes over the top of the brush. When this happens, the debris typically falls off the back end of the brush and is ejected out the back end of the sweeper.
Such sweepers can also generate a dust cloud while in operation. Suction can be used on side brushes and on the conveyor to control this dust. Regardless, a significant amount of dust is ejected into the atmosphere at least at the periphery of the brushes during sweeping. Besides being a nuisance, the dust is a source of particulate air pollution. In some localities particulate air pollution is a major problem, and municipalities are under government mandates to reduce particulate air pollution.
What is needed is a sweeper that can pick up a high percentage of road debris by recirculating debris that passes over the top of the main brush. Further, the sweeper should reduce the amount of dust ejected into the air. The present invention fulfills these and other needs, and addresses other deficiencies of prior art implementations.